Our 52" HP is breaking the deck belt tension spring quite frequently and the dealer can't figure it out. Sometimes it breaks the end off one end, and then both ends one time. They are breaking where they hook on. The first time they claimed we let the belt stretch too much and the spring was hitting a pulley. That went through two springs, Charged me a bunch $$ for that. The machine just busted another spring at 50 hours on that belt now they say they do not know what it is. We typically use double blades. Any help from your knowledge on this would be appreciated. The Machine has performed satisfactorly except for this.